The Parthenon and the Golden Proportion

Lesson One: Mathematical Calculations: The Source of Parthenon BeautyGoal:The learner will discover the relationship between mathematics and the aesthetic beauty of the Parthenon.

Objectives:As a result of this lesson the learner will know:

The significance of the Golden Rectangle in regard to aesthetic appeal. How the Greeks used math in overcoming problems with optical illusion. The importance of balance and symmetry in building design and sculpture. How math calculations contributed to the aesthetic appeal of the Athena

sculpture.

Background:The ancient Greeks would love the dynamics of modern math, science, and

technology – the computer, the split-second communications of the Internet and the cell phone, and the research into complex DNA. They would be especially excited by our “Golden Age of Astronomy” as mathematical calculations figure prominently in every aspect of today’s space age – from launching the space shuttle and making adjustments to the Hubble Telescope to exploring new solar systems and black holes. All these advances reinforce the notions of the Greek philosopher and mathematician, Pythagoras. His philosophy was distinguished by its description of Reality in terms of arithmetical relationships. Pythagorean mathematics had tremendous influence on the famous Greek philosopher Plato who, along with his followers at the Academy, believed that a study of mathematics held the key to all understanding. Carved above the doorway leading into the Academy of Plato (423-348 B.C.) were these words: Let no one ignorant of Geometry enter here.”

To the ancient Greeks, it was not numbers themselves that were important as the Egyptians and Babylonians believed, but the relationship between the numbers. These relationships were known as ratios and proportions. Through experimentation and the careful analysis and proof of findings, the ancient Greeks had already proven connections between math and nature, math and music, math and conceptual judgement. For example, a comparison of two things (mother:father, water:air, dog:cat) that we learn as babies is the most basic process of intelligence and the elementary basis for conceptual judgement, or how we figure things out. This comparison of two different things or ideas or quantities is a ratio or a measure of difference expressed in the formula a:b or a is to b.

A proportion is more complex because it is the relationship equivalency between two ratios, or one element is to the second element as the second element is to the third. It is more subtle and profound than the simple difference in a ratio and is known in Greek thought as an analogy. Students should keep these mathematical terms in mind as they explore characteristics of Greek architecture, especially their reliance upon the Golden Rectangle (also referred to as the Golden Proportion) and optical illusion in designing and constructing the ancient Parthenon.

Activities:The following exercises meet the Gateway Standards for Algebra I – 3.0 (Patterns, Functions and Algebraic Thinking) and Algebra I – 5.0 (Spatial Sense and Geometric Concepts).

1. The Golden Rectangle or Golden ProportionTN. Math Standards 6.1 spi.9, 6.4.spi.9, and 7.3 spi.7.

The Greeks also saw the relationship between math and beauty and proved their theory that geometry is a way to create beauty and to give the illusion of perfection. These early mathematicians observed many proportional relationships in the natural world. One proportion that appears most often is the Golden Proportion. It is the ratio between two dimensions of a plane figure or the divisions of a line such that the smaller is to the larger as the larger is to the sum of the two, represented by the ratio 1:1.618 or roughly 3 to 5. The ancient Greeks considered this to be the perfect proportion and it shows up in nature as the golden spiral (evident in natural objects ranging from sea shells to pine cones) and the golden rectangle which figures prominently in ancient architecture, especially the Parthenon. The foundation of the Parthenon is composed of two golden rectangles corresponding with the two rooms of the building.

Describe the Golden Proportion as it relates to the Parthenon. (The ratio of the two rooms whereby the smaller is to the larger as the larger is to the sum of the two rooms.) The exterior of the Parthenon likewise fits into the golden proportion so that the ratio of the entablature (the area from the top of the columns to the top of the roof) is to the column as the column is to the sum of the two. The same proportion appears again inside the Naos that houses Athena. The double decking of columns surrounding the stature adds to the scale of the statue through the golden proportion whereby the top column is to the lower as the lower column is to the sum of the two.

Make a Golden Rectangle: Construct a Square (A, B. C. D with A & B at the top left

and right and D & C at the lower left and right). Mark E as the midpoint between DC.From midpoint E, draw a diagonal line to B.Extend the line DC so that the vertical line BC is the

midpoint of EF.Using a compass anchored at E, swing an arc from B to F.Extend a vertical line from F to G; then extend the line AB

to G.You have a Golden Rectangle.

2. Optical IllusionMathematical theories and computations were crucial to the

illusion of perfection that sets apart the Parthenon from other architectural structures. An optical illusion is often the result of our eye structure (specifically, the curvature of the retina), oscillation as our eyes shift between two figures, or tricks played by our minds. In constructing the Parthenon the ancient Greeks understood that the straight lines on buildings, when viewed from a distance, often appear to curve in unintended directions. In their efforts to construct a visually perfect building, the ancient Greeks calculated and made architectural adjustments. The three most important are:

Curvature of the horizontal lines Inclining of vertical lines

Slight bulge, or entasis of the columns.They knew, for example, that straight, horizontal lines, such as the

floor or ceiling, often appear to sag when viewed from a distance. To compensate, they constructed these lines on a curve – higher in the center and curving down on the ends.

They also understood that vertical lines, such as walls and columns, could appear to lean outward from the building. To compensate for this illusion, the Greeks made all vertical lines tilt in slightly. Likewise, the entasis provided a third source of curvature to the lines of the building.

www.parthenon.org

Other architectural refinements included minute adjustments in the setting of metopes and triglyphs, and the alignment and setting of columns. Through mathematical calculation and careful measurement to determine the exact degree of curvature, the Greeks assured these slight architectural adjustments created the graceful lines and illusion of perfection that make the Parthenon an architectural wonder. (Which of these architectural refinements contributes to the illusion of a Grecian urn as one looks down the row of columns on the porches?)

3. Spatial Sense and Geometric ConceptsTN. Math Standards 7.3 tpi.2 and 8.3 tpi.8.As mentioned earlier, the ancient Greeks’ constant striving for balance, symmetry, and perfection was reflected in all aspects of their art, architecture, public lives and personal fulfillment. Balance and symmetry were considered the hallmark of perfection. For example, in the personal live the goal was a perfect balance of intellectual, physical, and spiritual development. This is reflected in their use of gymnasiums as not merely a place to “work out” physically, but as a place for study and participation in intellectual discussion with the great philosophers. The art and architecture also reflected this desire for perfect balance and symmetry. Take a moment to discuss what these words mean to you. Balance is the combining of elements to create equilibrium. Symmetry is the arrangement of parts on opposite sides of a boundary so that the two halves are identical or mirror images. Following your field trip to the Parthenon in Nashville, discuss the building’s architecture and details including the Pediments, Friezes, and Athena Statue. How do each of these reflect balance and symmetry?

4. Proportion in the Athena StatuePraxitiles was a fourth century BC Greek sculptor of great

reknown. He is credited with developing the 8-head canon by which schulptors figure the proportions of the human body. This canon states that the size of the human body may be measured accurately and conveniently using the head size as a standard unit. With this measure, the adult body is approximately 8 heads tall. Alan LeQuire, sculptor of the Nashville Athena statue states, “It works for me. My head is 9” tall from chin to the top of the head and I am 6’ (or 72” tall). 8x9=72.”

As the ancient Greeks understood, distance can produce optical illusions that in art and architecture force the adjustment of lines in order to achieve the appearance of perfection. As we stand in the Naos and admire Alan LeQuire’s sculpture of Athena, what our eye sees is a perfectly proportioned figure. But, like the ancient Greeks, Alan understood that wherever we sit or stand in the Naos, we are looking at the 41’10” statue of Athena from a weird angle. In order to achieve the illusion of proportional perfection in his statue, Alan had to make adjustments to the sculpture. In other words, he turned to math. Lets look at just one of his adjustments: the size of Athena’s head. We have already explored the 8-head canon used in sculpting human figures. Alan understood that in order to achieve the illusion of perfection, he would have to increase the head size of Athena. Beginning with the 41’10” statue, he subtracted the 5 ft. base and the 4 ft. helmet, leaving 32’10” for the head and body of Athena.A) Now convert 32’10” into inches.B) By dividing these inches by 8, you’ll get the size of Athena’s head

according to the 8-head canon.

C) In order to increase the head size, divide the total number in “A” by 7 to give you the actual size of the head on the statue.

TN. Standards 6.4.spi.9; 7.3.spi.6; and 7.4.spi.7.